1// Copyright 2019 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package proto
6
7import (
8	"fmt"
9
10	"google.golang.org/protobuf/reflect/protoreflect"
11)
12
13// Reset clears every field in the message.
14// The resulting message shares no observable memory with its previous state
15// other than the memory for the message itself.
16func Reset(m Message) {
17	if mr, ok := m.(interface{ Reset() }); ok && hasProtoMethods {
18		mr.Reset()
19		return
20	}
21	resetMessage(m.ProtoReflect())
22}
23
24func resetMessage(m protoreflect.Message) {
25	if !m.IsValid() {
26		panic(fmt.Sprintf("cannot reset invalid %v message", m.Descriptor().FullName()))
27	}
28
29	// Clear all known fields.
30	fds := m.Descriptor().Fields()
31	for i := 0; i < fds.Len(); i++ {
32		m.Clear(fds.Get(i))
33	}
34
35	// Clear extension fields.
36	m.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
37		m.Clear(fd)
38		return true
39	})
40
41	// Clear unknown fields.
42	m.SetUnknown(nil)
43}
44